1. Field
This disclosure relates to wireless energy transfer, methods, systems and apparati to accomplish such transfer, and applications.
2. Description of the Related Art
Energy or power may be transferred wirelessly using a variety of techniques as detailed, for example, in commonly owned U.S. patent application Ser. No. 12/789,611 published on Sep. 23, 2010 as U.S. Pat. Pub. No. 2010/0237709 and entitled “RESONATOR ARRAYS FOR WIRELESS ENERGY TRANSFER,” and U.S. patent application Ser. No. 12/722,050 published on Jul. 22, 2010 as U.S. Pat. Pub. No. 2010/0181843 and entitled “WIRELESS ENERGY TRANSFER FOR REFRIGERATOR APPLICATION” the contents of which are incorporated in their entirety as if fully set forth herein. Prior art wireless energy transfer systems have been limited by a variety of factors including concerns over user safety, low energy transfer efficiencies and restrictive physical proximity/alignment tolerances for the energy supply and sink components.
It is generally acknowledged that the adoption of traditional residential and commercial solar photovoltaic (PV) panel installations have been hampered by the high costs of these solar power systems. Recent estimates suggest that as much as 50% of the system costs are associated with the solar PV panel installation process. The factors driving the high cost of solar PV panel installations may include:                Roof Danger: Installation work is generally performed on a roof, and such work may carry a substantial premium for Liability and Workman's Compensation Insurance due to the inherent danger.        Highly Skilled Labor: The complexity of solar PV panel installation may require an ensemble of highly trained tradesmen (roofers, carpenters, and electricians), contractors, and professional engineers, who command premium rates.        Site-Specific Design: Each installation may require site-specific engineering to optimize panel location, string design, and wiring configurations, to accommodate the individual roof pitch, solar orientation, and other building specific features. An installation comprising panels or strings with different illumination levels may need dedicated maximum power point tracker (MPPT) circuits to efficiently extract energy from the PV panels in those areas. The outputs of the MPPT circuits then need to be wired together or individually wired to an interior main inverter or battery charger. Without such site-specific optimization, output efficiency may be dramatically lower than expected.        Roof and Building Penetrations: Running wiring through roof structures or exterior walls may be an expensive and potentially trouble prone operation, compromising the weather tightness of the building.        High Fixed Costs: The installation costs may have a high fixed cost component, which means that the scale of the PV installation must be large enough (often 2 kW-3 kW) to amortize the installation costs. As a result, typical residential solar PV systems may cost upwards of $20,000, and may have unsubsidized payback periods exceeding twenty (20) years.        
In addition to high installation costs, traditional, wired, PV panels may be difficult to reconfigure and unreliable. These panels may need to be permanently wired into fixed locations making changes in configurations or repositioning troublesome since it may require rewiring and extending the electrical connections. In addition wired connections may make weatherproofing and sealing of the wires, connectors and circuit components in PV systems more difficult and may result in more failure points in the installed systems which may be exposed to extreme environmental conditions including extreme temperatures, high winds, rain, high ultra violet radiation, and the like.
Therefore a need exists for methods and designs that reduce the cost and complexity associated with wiring of PV panels.
Energy distribution over an area to moving devices or devices that may be often repositioned is unpractical with wired connections. Moving and changing devices create the possibility of wire tangles, tripping hazards, and the like. Wireless energy transfer over a larger area may be difficult when the area or region in which devices may be present may be large compared to the size of the device. Large mismatches in a source and device wireless energy capture modules may pose challenges in delivering enough energy to the devices at a high enough efficiency to make the implementations practical or may be difficult to deploy.
Therefore a need exists for methods and designs for energy distribution that is wire free but easy to deploy and configurable while may deliver sufficient power to be practical to power many household and industrial devices.